Infection of macaque monkeys with simian hemorrhagic fever virus (SHFV) causes a rapid onset, fatal hemorrhagic disease. In contrast, species of African monkeys, such as patas monkeys, African green monkeys and baboons, develop asymptomatic acute or persistent SHFV infections. High levels of viremia have been documented in persistently infected patas monkeys. Macaques inoculated with the blood of long term persistently infected patas monkeys rapidly develop hemorrhagic disease. SHFV is a BSL2 level agent which does not infect humans. The ultimate goal of this project is to develop a BSL2 animal model of viral hemorrhagic fever which can be used for the development and testing of "generic" countermeasures of hemorrhagic disease. The hemorrhagic disease caused by SHFV in macaques is very similar to that caused by other BSL4 hemorrhagic fever viruses such as Ebola Zaire virus. The dramatic difference in disease outcome observed between macaques and African monkeys, even though SHFV replicates efficiently in both types of animals provides a unique system for dissecting the viral and host factors involved in triggering hemorrhagic disease. The construction and testing of a reverse genetic system for SHFV is proposed. This system will be used to begin the study of viral proteins involved in triggering host cell responses. Since essentially nothing is currently known about the cellular response to SHFV, comparative studies of SHFV replication in monocyte, macrophage and dendritic cell cultures from disease resistant and disease susceptible monkeys is proposed. Cell responses to SHFV will be assayed by a variety of methods. Proinflamnmtory cytokine production, tissue factor cell surface expression and gene expression patterns will be analyzed. This study will provide preliminary insights about the cellular factors/pathways and viral proteins that trigger or prevent a hemorrhagic response to SHFV infection and will provide reagents needed for further development of this model. The long term goal of this project is the development of a new BSL2 model of viral hemorrhagic fever that will be valuable for testing novel "generic" therapies for the treatment of hemorrhagic disease. Viral reagents needed for the further development of this model will be generated and preliminary comparative studies of the initial responses to simian hemorrhagic fever virus in cells from disease resistant and susceptible monkeys will provide further insights into the mechanisms involved in triggering viral hemorrhagic disease. [unreadable] [unreadable] [unreadable]